1. Field of the Invention
The present invention relates to a display device and an electronic device having the same, and more particularly to a configuration suitable for a display capable of switching a display screen between a display mode and a mirror mode.
2. Related Art
Traditionally, a display device has been known in which two liquid crystal panels are overlaid to switch between the display mode to perform normal display and the mirror mode to change the whole piece into a mirror surface state. For example, there is a display device in which a display switching part is disposed on the viewing side of a display part having the same structure as the general liquid crystal display device and the display switching part is disposed with a reflective type polarizer, a liquid crystal panel and an absorption type polarizer sequentially from the display part side to the viewing side. In this display device, the reflective type polarizer (hereafter, it is simply called reflective polarizer) of the display switching part transmits a first polarized light, and reflects a second polarized light having a polarization axis orthogonal to the first polarized light. The liquid crystal panel is configured to allow switching between the state that the first polarized light is changed to the second polarized light for transmission and the state that the polarization axis is not changed for transmission. The absorption type polarizer transmits the first polarized light and absorbs the second polarized light, for example. The display part emits the first polarized light to the display switching part, and the first polarized light forms a predetermined display image.
In the display device configured as above, when the liquid crystal panel of the display switching part is in the state that the polarization axis is not changed for transmission, the first polarized light emitted from the display part passes through the reflective polarizer to enter the liquid crystal panel and passes through the absorption type polarizer as the first polarized light for observation. Thus, the display condition of the display part can be visibly recognized (the display mode). When the liquid crystal panel is in the state that the first polarized light is changed into the second polarized light for transmission, the first polarized light emitted from the display part passes through the reflective polarizer to enter the liquid crystal panel, and it is changed into the second polarized light. Thus, it is absorbed by the absorption type polarizer and the display condition is not visually recognized. At this time, when an outside light enters the device, the outside light passes through the absorption type polarizer to be a first polarized light and passes through the liquid crystal panel to be a second polarized light. Therefore, it is reflected by the reflective polarizer, and it passes through the liquid crystal panel again to be changed into the first polarized light, and it passes through the absorption type polarizer. Accordingly, the display plane is visibly recognized as a mirror surface (the mirror mode).
In the traditional display device, the light having passed through the liquid crystal panel, disposed in the display switching part, is visibly recognized in both the display mode and the mirror mode. Therefore, the following problems tend to occur: a reduction in contrast due to the interface reflection in the front and back sides of the display switching part, coloring, the deterioration of the viewing angle property, and a blurred display image due to the optical property of the display switching part. In any case, in the traditional display device, degraded display quality is inevitable due to the double structure of the display part and the display switching part.
Furthermore, in the configuration described above, the display switching part including the liquid crystal panel is further disposed on the viewing side of the normal display part. Thus, there is a problem that the device becomes thicker and heavier. This problem becomes a great disadvantage because portability is impaired, particularly, when the device is mounted in a portable electronic device.
To solve the above problems, the present invention provides a novel configuration of a display device capable of suppressing the degradation of display quality such as a reduction in contrast, coloring, a narrowed viewing angle and blurring due to the existence of the display switching part, and is formed to be low-profile and light-weight.